1. Field
The invention relates to wireless devices. More particularly, the invention relates to wireless devices that are capable of synchronizing with other wireless devices.
2. Background
In some networks, wireless devices derive timing information from an external time source, for example, the Global Position System (GPS). However, the external time source may not always be available to a wireless device. For example, the wireless device may be located indoors and may not be able to derive timing information from GPS. When an external time source is unavailable, a plurality of collocated wireless devices may form a peer group. The peer group may have a group lead that periodically transmits a local timing signal allowing the wireless devices in the peer group to synchronize their clocks with the lead and communicate with each other synchronously.
These local timing signals, however, will not match the timing signals of other peer groups. To communicate synchronously with another device in the peer group, a wireless device must first receive the local timing signal and then synchronize with the local timing signal. Thus it is important that the group lead transmit a robust and regular timing signal. This places a large synchronization energy burden on the group lead. In addition, it is important that wireless devices in the peer group regularly monitor the timing signal to maintain synchronization. This places a synchronization energy burden on each of the devices in the peer group.
Accordingly, there is a need for apparatuses and methods that reduce the synchronization energy burden for wireless devices that use local timing. Aspects of the invention address this need as well as other needs.